The Cystic Fibrosis Core Center at Case Western Reserve University has three main areas of focus- epithelial cell biology, inflammation and host defense in the lung, and clinical studies in cystic fibrosis (CF). The epithelial cell biology effort is mainly in the areas of ion transport, intracellular signalling, and epithelial cell differentiation . The lung inflammation and host defenses effort focuses on mucosal immunity and the impact of persistent neutrophilic infiltration on the function of the host's defenses. Clinical studies include investigations on the pathophysiology of the CF lung disease, as well as three clinical trials now in progress and another in the pilot stages. The Center is devoted to discovering the underlying defect in CF, elucidating the nature of the pulmonary disease which takes the patients' lives, and in translating advances at the lab bench to the bedside as rapidly as is safe. The work is supported by an Administrative Component and six other Core facilities: the Patient Core, Cell Physiology Core, Epithelial Cell Culture Core, Inflammatory Mediator Core, Morphology Core, and Bronchoalveolar Lavage/Immunology Core. In addition, a pilot and feasibility program is proposed for continuation with three projects: one project by Dr. Michael Infeld on the determinants of mucous differentiation of epithelial cells is proposed for continuation; Dr. Michael Konstan proposes a one-year project designed to establish the feasibility of a clinical trial of antiproteases in CF; and Dr. Thomas Gerken proposes to obtain a mucus-secreting intestinal epithelial cell line which he can label with 13 C precursors in order to examine, by nuclear magnetic resonance, the intramolecular interactions in mucins both in the secretory granules and as they are released.